Various types of systems and methodologies are known in the art for tracking items. Tracking an item may involve locating or identifying a stationary object (a car key, book, or file, for example) that has been temporarily misplaced. One example of such a system is referred to as an inventory control system. When the object is valuable, such as with jewelry, or the key to a vehicle, it may be desirable to control access to the object, or to locate the object within a predetermined area. Tracking can also involve a continuous monitoring of a moving object (personnel or vehicles, for example) over a period of time.
It is known in the art to utilize radio frequency identification (“RFID”) technology for tracking objects. Generally, an RFID tag is attached to each object to be tracked. Typically, each tag has data stored on in that is associated with the object to which the tag is attached. Usually, the tag will contain an identification number that uniquely identifies the associated object, but the tag may contain other data as well. Conventional RFID tracking systems comprise an interrogator that scans for tags by transmitting an interrogation signal at a known frequency. RFID tags that are within range of the interrogator are activated and respond to the interrogator with a response signal that contains data associated with the object, such as an RFID tag ID. The interrogator detects the response signal and decodes that data, such as the RFID tag ID. Additionally, an interrogator can use a known tag ID to interrogate the specific RFID tag identified by the tag ID to receive stored data associated with the object to which the tag is attached. The act of an interrogator capturing stored data is commonly called an RFID read and the device doing the interrogating is commonly called an RFID reader.
One example of a tracking system utilizing RFID technology is the key tracking system disclosed in U.S. Pat. No. 6,204,764 issued to Maloney (“Maloney”), the disclosure of which is hereby incorporated by reference. The system disclosed in Maloney is limited in that the system requires a plurality of receptacles and the RFID tags are only activated when the associated object is placed in a receptacle. A second disadvantage of the system disclosed in Maloney is that it requires a separate transceiver for each storage receptacle within the storage box. A third disadvantage of the system disclosed in Maloney is the potential for signal collision when multiple objects are put in the same receptacle.